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Rosemount 755 Instruction Manual

Rosemount 755 Instruction Manual

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Rosemount Analytical
M
755
ODEL
O
A
XYGEN
NALYZER
I
M
NSTRUCTION
ANUAL
748183-H

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  • Page 1 Rosemount Analytical ODEL XYGEN NALYZER NSTRUCTION ANUAL 748183-H...
  • Page 2 Paliney No. 7™ is a trademark of J. M. Ney Co. ® SNOOP is a registered trademark of NUPRO Co. Manual Part Number 748183-H November 1997 Printed in U.S.A. Rosemount Analytical Inc. 4125 East La Palma Avenue Anaheim, California 92807-1802...

  • Page 3: Table Of Contents

    1. I ECTION NTRODUCTION RANGE OPTIONS..................1-1 1.1.1 Standard Zero-Based Range Options .........1-1 1.1.2 Standard Zero-Suppressed Range Options ........1-3 1.1.3 Special Range Options ...............1-3 ISOLATED CURRENT OUTPUT OPTIONS..........1-5 ALARM OPTION..................1-5 CASE MOUNTING OPTIONS ..............1-5 ELECTRICAL OPTIONS ................1-5 748183-H November 1997 Rosemount Analytical...
  • Page 4 755 O ODEL XYGEN NALYZER 2. I ECTION NSTALLATION UNPACKING.................... 2-1 LOCATION....................2-1 2.2.1 Location and Mounting ............... 2-1 VOLTAGE REQUIREMENTS ..............2-1 ELECTRICAL CONNECTIONS..............2-2 2.4.1 Line Power Connections............. 2-2 2.4.2 Recorder Output Selection and Cable Connections ....2-2 2.4.3...
  • Page 5 POWER SUPPLY., ±15VDC ..............6-1 CASE HEATER CONTROL CIRCUIT ............6-1 DETECTOR HEATER CONTROL CIRCUIT ..........6-5 DETECTOR LIGHT SOURCE CONTROL CIRCUIT ........6-6 DETECTOR WITH FIRST STAGE AMPLIFIER........6-7 FINAL OUTPUT AMPLIFIER ..............6-10 ZERO SUPPRESSION MODULE FOR ZERO ADJUSTMENT ....6-11 748183-H November 1997 Rosemount Analytical...
  • Page 6 755 O ODEL XYGEN NALYZER 7. S ECTION ERVICE AND AINTENANCE INITIAL CHECKOUT WITH STANDARD GASES........7-1 CHECKOUT AT TEST POINTS ON CASE CIRCUIT BOARD....7-2 DETECTOR COMPONENT CHECKOUT ..........7-4 7.3.1 Detector ..................7-4 7.3.2 Source Lamp ................7-4 7.3.3...
  • Page 7 Model 755 - Location of Major Components..........1-4 Electrical Interonnection ................2-3 Control Board - Adjustment Locations ............2-4 Potentiometric Recorder with Non-Standard Span ........2-5 Model 755 Connected to Drive Current-Activated Output Devices ...2-6 Typical Alarm Settings................2-7 Relay Terminal Connections ..............2-8 Alarm Relay Option Schematic Diagram ..........2-9 Connection of Typical Gas Selector Panel to Model 755......2-12...
  • Page 8 Schematic Diagram, Case Board 620434 Schematic Diagram, Isolated Current Output Board 624549 Pictorial Wiring Diagram, Model 755 632349 Installation Drawing, Model 755 - General Purpose 638277 Schematic Diagram, Alarm 643127 Installation Drawing, Model 755 Explosion-Proof 652188 Schematic Diagram, Control Board...

  • Page 9: Preface

    NTENDED TATEMENT The Model 755 is intended for use as an industrial process measurement device only. It is not intended for use in medical, diagnostic, or life support applications, and no independent agency certifications or approvals are to be implied as covering such application.
  • Page 10 NALYZER WARNING: POSSIBLE EXPLOSION HAZARD The general purpose Model 755 Oxygen Analyzer, catalog number 191102, is for operation in non-hazardous locations. It is of a type capable of analysis of sample gases which may be flammable. If used for analysis of such gases, the...

  • Page 11: Specifications - General

    Zero and span drift specifications based on following conditions: Operating pressure constant; ambient temperature change from initial calibration temperature, less than 11.1 Celsius degrees (20 Fahrenheit degrees); deviation from set flow held to within ±10% or ±20 cc/min, whichever is smaller. November 1997 Rosemount Analytical 748183-H...

  • Page 12: Specifications - Sample

    755 O ODEL XYGEN NALYZER PECIFICATIONS AMPLE RYNESS Sample dewpoint below 43°C (110°F), sample free of entrained liquids. EMPERATURE IMITS Maximum: 66°C (150°F) Minimum: 10°C (50°F) PERATING RESSURE Maximum: 69 kPa (10 psig). Minimum: 88.1 kPa absolute (660 mm Hg absolute pressure)
  • Page 13 When installed with user supplied components, meets requirements for Class I, Division 2 locations per National Electrical Code (ANSI/NFPA 70) for analyzers sampling nonflammable gases. Analyzers sampling flammable gases must be protected by a continuous dilution purge system in accordance with Standard ANSI/NFPA 496-1986, Chapter 8. Consult factory for recommendations. November 1997 Rosemount Analytical 748183-H...

  • Page 14: Customer Service, Technical Assistance And Field Service

    Technical Services Department at: Rosemount Analytical Inc. Phone: 1-714-986-7600 FAX: 1-714-577-8006 OCUMENTATION The following Model 755 Oxygen Analyzer instruction materials are available. Contact Customer Service or the local representative to order. 748183 Instruction Manual (this document) 748183-H Rosemount Analytical...

  • Page 15: Compliances

    ENERAL URPOSE NCLOSURE The Model 755 Oxygen Analyzer (general purpose enclosure), catalog number 191102, has been designed to meet the applicable requirements of the U.S. Occupational Safety and Health Act (OSHA) of 1970 if installed in accordance with the requirements of the National Electrical Code (NEC) of the United States in non- hazardous areas and operated and maintained in the recommended manner.
  • Page 16 755 O ODEL XYGEN NALYZER OTES 748183-H Rosemount Analytical November 1997...

  • Page 17: Introduction

    See Figures 1-1. 1.1 RANGE OPTIONS The Model 755 is supplied, as ordered, with four switch-selectable ranges: an overall range and three sub-ranges, each covering a portion of the overall range. standard range options are of two general types: zero-based (Section 1.1.1) and zero- suppressed (Section 1.1.2).

  • Page 18: Model 755 - Front View

    XPLOSION ROOF NCLOSURE Meter ZERO Control SPAN Adjust RANGE Switch Model 755 Rosemount Analytical Oxygen Analyzer Controls have slotted shafts for screwdriver adjustment from outside the enclosure. 1-1. M 755 - F IGURE ODEL RONT Rosemount Analytical November 1997 748183-H...

  • Page 19: Special Range Options

    1.1.3 S PECIAL ANGE PTIONS On factory special order, the analyzer may be provided with a special range option incorporating any desired combination of zero-based and zero-suppressed ranges, arranged in ascending order according to span. 748183-H November 1997 Rosemount Analytical...

  • Page 20: Model 755 - Location Of Major Components

    Detector/Magnet AC Power Assembly Shock Mount Transformer, Power Detector/Magnet Assembly (Behind TB1) General Purpose enclosure shown. Components mounted in same locations in Explosion-Proof enclosure. 1-2. M 755 - L IGURE ODEL OCATION OF AJOR OMPONENTS Rosemount Analytical November 1997 748183-H...

  • Page 21: Isolated Current Output Options

    1.4 CASE MOUNTING OPTIONS General Purpose Enclosure, see drawing 632349. Explosion Proof Enclosure, see drawing 643127. 1.5 ELECTRICAL OPTIONS The analyzer is supplied, as ordered, for operation on either 120 VAC, 50/60 Hz, or 240 VAC, 50/60 Hz. 748183-H November 1997 Rosemount Analytical...
  • Page 22 755 O ODEL XYGEN NALYZER OTES Rosemount Analytical November 1997 748183-H...

  • Page 23: Installation

    Do not operate without doors and covers secure. Servicing requires access to live parts which can cause death or serious injury. Refer servicing to qualified personnel. For safety and proper performance this instrument must be connected to a properly grounded three-wire source of power. 748183-H November 1997 Rosemount Analytical...

  • Page 24: Electrical Connections

    755 O ODEL XYGEN NALYZER Note Refer to Installation Drawing 632349 or 643127 at the rear of this manual for recommended cable conduit openings. CAUTION: ENCLOSURE INTEGRITY With reference to Installation Drawing 632349 or 643127, any unused cable conduit openings must be securely sealed by permanent closures in order to provide enclosure integrity in compliance with personnel safety and environmental protection requirements.
  • Page 25 Explosion-Proof Enclosure General Purpose Enclosure NO. 1 RESET NO. 2 + - + mV Recorder RESET mA Recorder Power Connections (see below) Jumpers Jumper 120 VAC CONFIGURATION 240 VAC CONFIGURATION 2-1. E IGURE LECTRICAL NTERCONNECTION 748183-H November 1997 Rosemount Analytical...
  • Page 26 755 O ODEL XYGEN NALYZER OTENTIOMETRIC UTPUT 1. Insert RECORDER OUTPUT Selector Plug (Figure 2-2) in position appropriate to the desired output: 10 mV, 100 mV, 1 V, or 5 V. 2. On TB2, Figure 2-1, connect leads of shielded recorder cable to MV+ and COM terminals.
  • Page 27 20 mA, and 4 for 4 to 20 mA. b. With analyzer meter at fullscale, adjust R2 for desired fullscale current (typically 20 mA). 7. Current and voltage outputs may be utilized simultaneously, if desired. 748183-H November 1997 Rosemount Analytical...

  • Page 28: Output Connections, Initial Setup For Dual Alarm Option

    755 O ODEL XYGEN NALYZER Recorder Analyzer Controller Remote Indicator 2-4. M 755 C IGURE ODEL ONNECTED RIVE URRENT UTPUT CTIVATED UTPUT EVICES 2.4.3 O UTPUT ONNECTIONS NITIAL ETUP FOR LARM PTION If so ordered the analyzer is factory-equipped with alarm output. Alternatively the alarm feature is obtainable by subsequent installation of the Alarm Kit.

  • Page 29: Typical Alarm Settings

    RESET terminals on the Alarm Relay Assembly, see Figure 2-1. If the corresponding relay is now de- energized, i.e., in alarm condition, the relay remains de-energized until the operator momentarily closes the switch. 748183-H November 1997 Rosemount Analytical...

  • Page 30: Relay Terminal Connections

    755 O ODEL XYGEN NALYZER REQUIREMENT TYPICAL CONNECTIONS REQUIREMENT TYPICAL CONNECTIONS Solenoid Valve No. 1 No. 1 115 VAC Alarm Bell or Lamp 115 VAC RESET RESET Low Control Low Alarm, Limit, Fail-Safe Fail-Safe RESET RESET No. 2 No. 2 No.

  • Page 31: Alarm Relay Option Schematic Diagram

    2. RELAYS SHOWN IN ENERGIZED POSITION. 1. CR1 AND CR2 ARE ANY 600 V, 1 AMP DIODE. NOTES: 2-7. A IGURE LARM ELAY PTION CHEMATIC IAGRAM 6. Calibration of ALARM 2, LOW. a. Rotate setpoint adjustment, R68, fully counter-clockwise. 748183-H November 1997 Rosemount Analytical...

  • Page 32: Calibration Gases

    755 O ODEL XYGEN NALYZER b. Adjust SPAN control for display or recorder reading exactly fullscale. If the fullscale setting cannot be reached, then set to a reading higher than the desired alarm setpoint. c. Set ALARM 2 calibration adjustment, R67, to its clockwise limit. Rotate R67 counter-clockwise, the minimum amount required to energize ALARM 2, relay K2.

  • Page 33: Calibration

    A zero-suppressed range uses a blend consisting of a suitable percentage of oxygen contained in a background gas. typically nitrogen. (An alternative calibration method, described in Section 3.2.2, uses an upscale standard gas only and does not require a downscale standard gas.) 2-11 748183-H November 1997 Rosemount Analytical...

  • Page 34: Downscale Standard Gas

    755 O ODEL XYGEN NALYZER 2.5.2 U PSCALE TANDARD A suitable upscale standard gas is required to establish a calibration point at or near the upper range limit. If this range limit is 215% or 25% oxygen, the usual upscale standard gas is air (20.93% oxygen).

  • Page 35: Normal Operation At Positive Gauge Pressures

    Normally the sample is supplied to the analyzer inlet at a positive gauge pressure in the range of 0 to 10 psig (0 to 69 kPa). CAUTION: HIGH PRESSURE SURGES High pressure surges during admission of sample or standard gases can damage the detector. 2-13 748183-H November 1997 Rosemount Analytical...

  • Page 36: Operation At Negative Gauge Pressures

    755 O ODEL XYGEN NALYZER AMPLE XHAUST With positive sample pressure, the proper choice of arrangement for sample exhaust depends principally on whether the analyzer has zero-based or zero-suppressed ranges. as explained below. AMPLE XHAUST RRANGEMENTS FOR ASED ANGES With zero-based ranges, the analyzer exhaust port is commonly vented directly to the atmosphere, and any change in barometric pressure results in a directly proportional change in the indicated percentage of oxygen.

  • Page 37: Corrosive Gases

    Internal leakage of sample resulting from failure to observe these precautions could result in an explosion causing death, personal injury, or property damage. 2-15 748183-H November 1997 Rosemount Analytical...

  • Page 38: Purge Kit (Optional)

    2.8 PURGE KIT (OPTIONAL) The optional 643108 Purge Kit is designed to equip the Model 755 General Purpose enclosure with Type Z Air Purge per National Fire Protection Association Standard NFPA 496-1986, Chapter Two.

  • Page 39: Installation Of Purge Kit

    Inlet Fitting Outlet Fitting Inlet Fitting Purge Purge Supply Supply Flow Pressure Indicator Indicator or Alarm 645835 Purge Outlet Fitting Components in dashed line are supplied by customer. 2-9. I IGURE NSTALLATION OF URGE 2-17 748183-H November 1997 Rosemount Analytical...
  • Page 40 755 O ODEL XYGEN NALYZER OTES 2-18 November 1997 Rosemount Analytical 748183-H...

  • Page 41: Startup

    Preparatory to start-up and calibration, a familiarization with Figures 1-1, 1-2 and 3-1, and Tables 3-1 is recommended. These figures give locations and summarized descriptions of components and operating adjustments of the Model 755. Open analyzer door and verify that circuit boards are properly installed and connected.

  • Page 42: Control Board - Adjustment Locations

    755 O ODEL XYGEN NALYZER performed on the range of highest sensitivity, i.e., most narrow span. Preferably upscale calibration should be performed on the range that will be used during sample analysis. In some applications however, it may be desirable to perform upscale calibration on a range of higher sensitivity, i.e., more narrow span, and then move the...

  • Page 43: Control Board - Adjustment Functions

    15. ALARM 1 C (R63) ALIBRATION DJUSTMENT 16. ALARM 1 S (R64) ETPOINT DJUSTMENT 17. ALARM 1 D (R73) EADBAND DJUSTMENT Functions identical to the corresponding adjustment for ALARM 2 circuit. 3-1. C ABLE ONTROL OARD DJUSTMENT UNCTIONS 748183-H November 1997 Rosemount Analytical...
  • Page 44 755 O ODEL XYGEN NALYZER A. ZERO BASED RANGES RANGE RECOMMENDED DOWNSCALE RECOMMENDED UPSCALE STANDARD GAS STANDARD GAS 0 to 1 Nitrogen 0.9% O , balance N 0 to 2.5 Nitrogen 2.3% O , balance N 0 to 5 Nitrogen 4.5% O...

  • Page 45: Gas Only

    6. Repeat Steps 4b and 5 as many times as necessary until no readjustment is required after switch-over from one range to the other. 7. To verify accurate calibration, admit an on-scale gas other than the upscale standard. and check that the indicated oxygen concentration is correct. 748183-H November 1997 Rosemount Analytical...

  • Page 46: Compensation For Composition Of Background Gas

    755 O ODEL XYGEN NALYZER EXAMPLE Range, 90% to 100% oxygen Upscale Standard Gas, 99.7% oxygen 8. Set % RANGE Switch for 90% to 100% oxygen. Then adjust SPAN Control for recorder reading of 99.7% oxygen. Return % RANGE Switch to 99% to 100% range.

  • Page 47: Oxygen Equivalent Values Of Gases

    = 0.8 x (-0.623) + 0.2 x (-0.358) neo-Pentane, C -1.853 = (-0.4984) + (-0.07l6) Propane, C -1.135 = 0.570% O Propylene, C -0.903 Water, H -0.381 Xenon, Xe -1.340 3-3. O ABLE XYGEN QUIVALENT OF OMMON ASES 748183-H November 1997 Rosemount Analytical...
  • Page 48 755 O ODEL XYGEN NALYZER EXAMPLE: ZERO-SUPPRESSED RANGE Range 50% to 100% oxygen At lower range-limit, i.e., 50% oxygen composition of sample is: 50% oxygen: 30% CO : 20% N From Table 3-4, the % oxygen equivalents are: O + 100%, CO , -0.623%;...
  • Page 49 The meter scale is not calibrated with negative values; however, a negative value may be set on the recorder if provided with below-zero capability.) 748183-H November 1997 Rosemount Analytical...
  • Page 50 755 O ODEL XYGEN NALYZER OTES 3-10 November 1997 Rosemount Analytical 748183-H...

  • Page 51: Operation

    Pst = Operating pressure during standardization Pan = Operating pressure during sample analysis EXAMPLE (U.S. Units) Pst = 760 mm Hg Pan = 740 mm Hg Indicated % O = 40% True % O = 40% = 41.1% O December 1997 748183-H Rosemount Analytical...

  • Page 52: Calibration Frequency

    755 O ODEL XYGEN NALYZER EXAMPLE (S.I. Units) Pst = 101 kPa Pan = 98.2 kPa Indicated % O = 40% True % O = 101/98.2 x 40% = 41.1% O 4.3 CALIBRATION FREQUENCY The appropriate calibration interval will depend on the accuracy required in the particular application, and is best determined by keeping a calibration log.

  • Page 53: Theory

    Diamagnetic gases are analogous to non-magnetic substances. With the Model 755, the volume magnetic susceptibility of the flowing gas sample is sensed in the detector/magnet assembly. As shown in the functional diagram of Figure 5-1, a dumbbell-shaped nitrogen-filled hollow glass test body is suspended on a platinum/nickel alloy ribbon in a non-uniform magnetic field.

  • Page 54: Measurement System

    755 O ODEL XYGEN NALYZER Displacement Torque Electromagnetic Restoring Axis Torque Restoring Balancing Weight Current Electromagnetic Axis Nitrogen-Filled Hollow Glass Test Body Titanium Wire Conductor Mirror Restoring Current Balancing Weight Platinum/Nickel Alloy Suspension Ribbon TEST BODY DETAIL Displacement Torque Restoring...

  • Page 55: Magnetic Displacement Force

    Sphere (Magnetic Susceptibility = k Sample Gas (Magnetic Susceptibility = k ) Note: As percentage of oxygen in sample gas increases, displacement force (F ) increases. 5-2. S IGURE PHERICAL ODY IN NIFORM AGNETIC IELD 748183-H December 1997 Rosemount Analytical...

  • Page 56: Physical Configuration Of Detector/Magnet Assembly

    755 O ODEL XYGEN NALYZER 5.1.2 P HYSICAL ONFIGURATION OF ETECTOR AGNET SSEMBLY As shown in the exploded view of Figure 5-3A, the detector/magnet assembly consists of three major subassemblies: the magnet assembly, the detector assembly, and the optical bench assembly.

  • Page 57: Variables Influencing Paramagnetic Oxygen

    RESSURE FFECTS Although normally calibrated for readout in percent oxygen, the Model 755 actually responds to oxygen partial pressure. The partial pressure of the oxygen component in a gas mixture is proportional to the total pressure of the mixture. Thus readout is affected by pressure variations.

  • Page 58: Temperature Effects

    FFECTS Magnetic susceptibilities and partial pressures of gases vary with temperature. In the Model 755, temperature-induced readout error is avoided by control of temperatures in the following areas: 1. Interior of the analyzer is maintained at 140°F (60°C) by an electrically controlled heater and associated fan.

  • Page 59: Electronic Circuitry

    AR2, to permit establishing a downscale calibration point on the meter scale or recorder chart. With downscale standard gas flowing through the analyzer, the ZERO control is adjusted for the appropriate reading. 748183-H December 1997 Rosemount Analytical...

  • Page 60: Case Board Assembly

    755 O ODEL XYGEN NALYZER If the analyzer is to incorporate a zero-suppressed range option, the required zero offset is obtained by insertion of the zero suppression resistor module into receptacle J6. This module may be inserted either during factory assembly or in subsequent field installation of a range conversion kit.

  • Page 61: Alarm Option

    The alarm has two single-pole, double- throw relays, one each for the ALARM 1 and ALARM 2 contacts. Alarm output connections are on the terminal board shown in Figure 1-2. 748183-H December 1997 Rosemount Analytical...
  • Page 62 755 O ODEL XYGEN NALYZER OTES 5-10 Rosemount Analytical December 1997 748183-H...

  • Page 63: Section 6. Circuit Analysis

    IRCUIT NALYSIS The electronic circuitry of the Model 755 Oxygen Analyzer consists of the following: • Case heater circuit • Detector heater circuit • ±15 VAC power supply • Voltage regulating circuit for a stable light source • Detector circuit with a first-stage amplifier to provide a feedback current for mechanical feedback to the detector and a scaling amplifier circuit to give an output change of 0 to +7.5 V for a 0 to 100% change of the operating span.
  • Page 64 755 O ODEL XYGEN NALYZER 100µ -1.7V -15V 159mV 180 ° 360° 180° 0° 0° COMP 1 COMP 2 +15V +15V U1-A OUTPUT 21.5K -15V +15V U1-B 3.3K -15V INPUT 4.75K 0.18uF -1.88 VDC Source CASE BOARD 6-1. T OR C...
  • Page 65 -15V -2.3V 6 Hz 249K +15V +15V U1-C INPUT FROM 590K MULTIVIBRATOR -15V 1.0uF 210K -15V to 1.88V ±0.3V 63.4K 9.09K 37.4K 2200uF COMPARATOR -15V 56.2 .18uF 169K CASE BOARD -15V 6-3. R IGURE ENERATOR 748183-H December 1997 Rosemount Analytical...
  • Page 66 755 O ODEL XYGEN NALYZER On initial application of power to comparator of Figure 6-2, no potential exists on the inverting terminal because no charge exists on capacitor, C37. If the transistor of comparator 3 does not conduct, +15 V is at the output terminal. With +15 V at the output, the potential on the noninverting terminals will be about ±2.3V because of the...

  • Page 67: Detector Heater Control Circuit

    The thermistor resistance is 149 K at 150°F (65.5°C) and increases rapidly as the temperature decreases. R59 in this bridge circuit represents the set-point value for temperature. Suppose that, at temperature, 748183-H December 1997 Rosemount Analytical...

  • Page 68: Detector Light Source Control Circuit

    755 O ODEL XYGEN NALYZER resistance of the bridge (R55, R56, R59, and RT1) equals 149 K. If the temperature goes down, RT1 increases in resistance and causes the junction of RT1 and R59 to go positive in voltage value. Since R55 and R56 are of equal resistance, their junction is at zero volts.

  • Page 69: Detector With First Stage Amplifier

    Attached to the center arm of the test body dumbbell is a diamond-shaped mirror. Attached to the mirror are two separate platinum wires in tension with the supports for the test body. The supports are isolated from ground and are electrically connected to 748183-H December 1997 Rosemount Analytical...

  • Page 70: Detector With First Stage Amplifier

    755 O ODEL XYGEN NALYZER the feedback loop and the electronics for that loop. The platinum wires form a fulcrum around which the test body pivots. The detector operates in the following fashion. If the sample gas contains oxygen, it collects in the nonuniform magnetic field around the test body.
  • Page 71 The output of U3 is always 0 to +7.5 V. This is accomplished by RANGE Switch SW1, which selects some portion of the output and supplies this value as feedback to the input of U3. Adjustment of the input resistance R4 gives span trim adjustment once 748183-H December 1997 Rosemount Analytical...

  • Page 72: Final Output Amplifier

    755 O ODEL XYGEN NALYZER the range has been selected by Range Switch SW1. The output of U3 is picked off between R20 and R26 and brought into the final amplifier. The wiper of potentiometer R20 picks off a potential that helps give a little phase lead to the measurement circuit.

  • Page 73: Zero Suppression Module For Zero Adjustment

    RANGE Switch SW1. This divided, or selected, voltage is applied to the input of amplifier U2 (Figure 6-8) to provide the amount of zero suppression that corresponds to the lower range-limit of the zero- suppressed range. 6-11 748183-H December 1997 Rosemount Analytical...

  • Page 74: Zero Suppression Module

    755 O ODEL XYGEN NALYZER ZERO SUPPRESSION MODULE +15V PM REF 100K FRONT .033uF PANEL %RANGE +15V FRONT PANEL 232K ZERO .047uF -15V CONTROL BOARD 6-8. Z IGURE UPPRESSION ODULE 6-12 December 1997 Rosemount Analytical 748183-H...

  • Page 75: Ervice And

    Use only factory documented components for repair. 7.1 INITIAL CHECKOUT WITH STANDARD GASES If instrument readings do not meet specifications, the first step in troubleshooting is to isolate the analyzer from the sample stream and the sample-handling system. December 1997 748183-H Rosemount Analytical...

  • Page 76: Checkout At Test Points On Case Circuit Board

    755 O ODEL XYGEN NALYZER Admit downscale and upscale standard gases to the analyzer; observe readout on meter, and on recorder if used: Meter reads correctly with standard gases but not with sample gas, the sample and the sample-handling system are suspect. Check these areas.
  • Page 77 Checkout of the case circuit board is now complete. D C B D C B A + - + Case Board Alarm Option removed for clarity. 7-1. L A, B, C IGURE OCATIONS OF OARD OINTS 748183-H December 1997 Rosemount Analytical...

  • Page 78: Detector Component Checkout

    755 O ODEL XYGEN NALYZER CURRENT TO VOLTAGE OP AMPS ON CONNECTOR BOARD PHOTOCELLS SUSPENSION LOOP 7-2. V IGURE OLTAGE OINTS 7.3 DETECTOR COMPONENT CHECKOUT 7.3.1 D ETECTOR Before concluding that the detector is defective and must be replaced, verify that all components and circuits that could cause erratic readings are operating properly.

  • Page 79: Suspension

    Otherwise vibration waves could travel upward along the tubing walls, resulting in noisy readout. 3. Refer to Figure 7-3. Using needle-nose pliers, squeeze the hose clamps to disconnect the rubber sample lines from the metal inlet and outlet tubes of the detector assembly. 748183-H December 1997 Rosemount Analytical...

  • Page 80: Detector/Magnet Assembly

    755 O ODEL XYGEN NALYZER 4. Remove the two screws at the bottom of the detector assembly, slide detector out. 5. Install replacement detector assembly and connect cable to J12. 6. Seat the detector assembly firmly against the magnet pole pieces and tighten attaching screws.
  • Page 81 C. Removal and Insertion of Pin/Leads in Connector J12 Keeper Upper Slot Side View Connector Pin Removed of Connector Connector Pin/ Leads in Place Lower Slot Improvised Pin Removal Tool, Such as a Paper Clip 7-4. D IGURE ETECTOR AGNET SSEMBLY IRING 748183-H December 1997 Rosemount Analytical...

  • Page 82: Source Lamp Replacement And Adjustment

    755 O ODEL XYGEN NALYZER 7.4.2 S OURCE EPLACEMENT AND DJUSTMENT EPLACEMENT 1. Remove the four screws securing the detector assembly cover plate. 2. Refer to Figure 7-3. Carefully remove the small rubber hose connected from the detector/magnet assembly to the detector.
  • Page 83 Figure 7-6. The base of the lamp should extend from the hole approximately 1/4 inch, then tighten the set-screw. 1/4" Set Screw Red Mark for Alignment 7-6. L IGURE LIGNMENT The photocell will need realigning per subsection 7.4.3. 748183-H December 1997 Rosemount Analytical...

  • Page 84: Photocell Adjustment Voltmeter Lead Location

    755 O ODEL XYGEN NALYZER 7.4.3 P HOTOCELL EPLACEMENT AND LIGNMENT In removing photocells for examination, testing, or replacement, use the following procedure. The range resistor module, and zero suppression module. if used, must be installed. EPLACEMENT To remove the photocell from the optical bench, perform steps 1 thourgh 5 of Section 7.4.2.

  • Page 85: Heating Circuits

    Combined resistance of these two parallel-connected heaters, as measured at pins 15 and 16 of detector connector J12, should be approximately 17 ohms. If not, remove pin/leads 14 and 15 from the connector, to measure resistance of HR2 alone. 7-11 748183-H December 1997 Rosemount Analytical...
  • Page 86 755 O ODEL XYGEN NALYZER This resistance should be approximately 89 ohms. If resistance was correct, and yet the combined resistance was incorrect, heater HR1 may be open. To reach the leads of HR1. remove the printed circuit board on the heater assembly. Resistance of HR1 should be approximately 21 ohms.

  • Page 87: Replacement

    ARTS The following parts are recommended for routine maintenance and troubleshooting of the Model 755 Oxygen Analyzer. If the troubleshooting procedures do not resolve the problem, contact your local Rosemount Analytical service office. A list of Rosemount Analytical Service Centers is located in the back of this manual.
  • Page 88 755 O ODEL XYGEN NALYZER 622356 Photocell assembly 631773 Case circuit board assembly 623875 Control board assembly 632449 Fan (120 V) 632441 Fan (240 V) 861652 Heater (120 V) 861653 Heater (240 V) 620433 Current output board, 0 to 20 mA, 4 to 20 Ma...
  • Page 89 8. Do not place cylinders where they may become part of an electric circuit. When electric arc welding, precautions must be taken to prevent striking an arc against the cylinder. Rosemount Analytical Inc. 4125 E • A 92807-1802 • 714-986-7600 • FAX 714-577-8006...
  • Page 90 (blank)
  • Page 91 SUCCESSOR INTEREST TO THE GOODS PROVIDED HEREUNDER. Force Majeure. Seller shall not be liable for failure to perform due to labor strikes or acts beyond Seller's direct control. Rosemount Analytical Rosemount Analytical Inc. 4125 E • A 92807-1802 • 714-986-7600 • FAX 714-577-8006...
  • Page 92 (blank)
  • Page 93 National Response Center 1-800-654-7768 NTERNATIONAL Contact your local Rosemount Sales and Service office for service support. ACTORY For order administration, replacement Parts, application assistance, on-site or factory repair, service or maintenance contract information, contact: Rosemount Analytical Inc.
  • Page 94 (blank)

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